Upshot_Knothole

Operation Upshot–Knothole

Operation Upshot–Knothole

Series of 1950s US nuclear tests

See also: List of nuclear weapons tests of the United States

Operation Upshot–Knothole was a series of eleven nuclear test shots conducted in 1953 at the Nevada Test Site. It followed Operation Ivy and preceded Operation Castle.

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Over 21,000 soldiers took part in the ground exercise Desert Rock V in conjunction with the Grable shot.[1] Grable was a 280mm Artillery Fired Atomic Projectile (AFAP) shell fired from the "Atomic Cannon" and was viewed by a number of high-ranking military officials.

The test series was notable as containing the first time an AFAP shell was fired (GRABLE Shot), the first two shots (both fizzles) by University of California Radiation Laboratory—Livermore (now Lawrence Livermore National Laboratory), and for testing out some of the thermonuclear components that would be used for the massive thermonuclear series of Operation Castle. One primary device (RACER) was tested in thermonuclear system mockup assemblies of TX-14, TX-16, and TX-17/TX-24, to examine and evaluate the behaviour of radiation cases and the compression of the secondary geometries by the primary's x-rays prior to full-scale testing during Castle.[2]: 192  Following RACER's dodgy performance, the COBRA primary was used in the emergency capability ALARM CLOCK, JUGHEAD, RUNT I, RUNT II thermonuclear devices, as well as in the SHRIMP device.[2]: 200  RACER IV (as redesigned and proof-tested in the Simon test) was employed as primary for the ZOMBIE,[2]: 200  RAMROD and MORGENSTERN[2]: 318  devices.

Nuclear tests

Annie

Planned yield for Annie was 15 kilotonnes of TNT (63 TJ), actual yield based on radiochemical analysis was 16.2 kilotonnes of TNT (68 TJ).[3]

Nancy

Planned yield for Nancy was 40 kilotonnes of TNT (170 TJ), actual yield based on radiochemical analysis was 24.5 kilotonnes of TNT (103 TJ).[4]

Simon

Planned yield for Simon was 33 kilotonnes of TNT (140 TJ), actual yield based on radiochemical analysis was 43.4 kilotonnes of TNT (182 TJ).[5]

Harry

Planned yield for Harry was 37 kilotonnes of TNT (150 TJ), actual yield based on radiochemical analysis was 27 kilotonnes of TNT (110 TJ).[6]

Encore

Planned yield for Encore was 31 kilotonnes of TNT (130 TJ), actual yield based on radiochemical analysis was 26 kilotonnes of TNT (110 TJ).[7]

List of tests

More information Name, Date time (UT) ...
  1. [N 1]
    The US, France and Great Britain have code-named their test events, while the USSR and China did not, and therefore have only test numbers (with some exceptions – Soviet peaceful explosions were named). Word translations into English in parentheses unless the name is a proper noun. A dash followed by a number indicates a member of a salvo event. The US also sometimes named the individual explosions in such a salvo test, which results in "name1 – 1(with name2)". If test is canceled or aborted, then the row data like date and location discloses the intended plans, where known.
  2. [N 2]
    To convert the UT time into standard local, add the number of hours in parentheses to the UT time; for local daylight saving time, add one additional hour. If the result is earlier than 00:00, add 24 hours and subtract 1 from the day; if it is 24:00 or later, subtract 24 hours and add 1 to the day. Historical time zone data obtained from the IANA time zone database.
  3. [N 3]
    Rough place name and a latitude/longitude reference; for rocket-carried tests, the launch location is specified before the detonation location, if known. Some locations are extremely accurate; others (like airdrops and space blasts) may be quite inaccurate. "~" indicates a likely pro-forma rough location, shared with other tests in that same area.
  4. [N 4]
    Elevation is the ground level at the point directly below the explosion relative to sea level; height is the additional distance added or subtracted by tower, balloon, shaft, tunnel, air drop or other contrivance. For rocket bursts the ground level is "N/A". In some cases it is not clear if the height is absolute or relative to ground, for example, Plumbbob/John. No number or units indicates the value is unknown, while "0" means zero. Sorting on this column is by elevation and height added together.
  5. [N 5]
    Atmospheric, airdrop, balloon, gun, cruise missile, rocket, surface, tower, and barge are all disallowed by the Partial Nuclear Test Ban Treaty. Sealed shaft and tunnel are underground, and remained useful under the PTBT. Intentional cratering tests are borderline; they occurred under the treaty, were sometimes protested, and generally overlooked if the test was declared to be a peaceful use.
  6. [N 6]
    Include weapons development, weapon effects, safety test, transport safety test, war, science, joint verification and industrial/peaceful, which may be further broken down.
  7. [N 7]
    Designations for test items where known, "?" indicates some uncertainty about the preceding value, nicknames for particular devices in quotes. This category of information is often not officially disclosed.
  8. [N 8]
    Estimated energy yield in tons, kilotons, and megatons. A ton of TNT equivalent is defined as 4.184 gigajoules (1 gigacalorie).
  9. [N 9]
    Radioactive emission to the atmosphere aside from prompt neutrons, where known. The measured species is only iodine-131 if mentioned, otherwise it is all species. No entry means unknown, probably none if underground and "all" if not; otherwise notation for whether measured on the site only or off the site, where known, and the measured amount of radioactivity released.
  • Full uncut detonation of Upshot-Knothole Grable, launched out of the Atomic Annie device on 5/25/1953. The footage at normal speed is about 2+1⁄2 minutes.
  • Close-up slow motion shot of Grable fire-ball, mach-stem and surface effects,
  • Upshot-Knothole Encore, 27-kilotons.
  • Upshot-Knothole Ruth, 0.2-kilotons.
  • Upshot-Knothole Ruth, Note close proximity to highway in foreground as to the scale of detonation.
  • The mangled tower for the Ruth test. The explosion failed to level the testing tower, only somewhat damaging it.

References

Notes
  1. [N 1]
    Apparently the device name is a misnomer, as it implies that the device tested was related to the TX-15 "ZOMBIE". However, this is not the case; no thermonuclear component testing of TX-15 appears to have been conducted during this operation, since Upshot-Knothole tested radiation implosion mockups, containing primaries and mocked-up secondaries with small amounts of enriched Li-6 for the TX-14, TX-16, and TX-17/24 thermonuclear prototype systems, all slated to be proof-fired during CASTLE.[2]: 193 
Citations
  1. [1]
    Operation UPSHOT-KNOTHOLE Fact Sheet Archived February 18, 2013, at the Wayback Machine, Defense Threat Reduction Agency
  2. [2]
    Hansen, Chuck (1995). Swords of Armageddon. Vol. III. Retrieved December 28, 2016.
  3. [3]
    Rogin, Leo; DuPont, Alden C; Weeber, Christian G. Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight (Report). NAVAL AIR MATERIAL CENTER PHILADELPHIAPA. p. 25. Retrieved September 30, 2023.
  4. [4]
    Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight, p. 28.
  5. [5]
    Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight, p. 32.
  6. [6]
    Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight, p. 36.
  7. [7]
    Operation Upshot-Knothole. Project 5.1. Atomic Weapon Effects on AD Type Aircraft in Flight, p. 41.
  8. [8]
    "Time Zone Historical Database". iana.com. Retrieved March 8, 2014.
  9. [9]
    Estimated exposures and thyroid doses received by the American people from Iodine-131 in fallout following Nevada atmospheric nuclear bomb tests, Chapter 2 (PDF), National Cancer Institute, 1997, retrieved January 5, 2014
  10. [10]
    Sublette, Carey, Nuclear Weapons Archive, retrieved January 6, 2014
  11. [11]
    Hansen, Chuck (1995), The Swords of Armageddon, Vol. 8, Sunnyvale, CA: Chukelea Publications, ISBN 978-0-9791915-1-0
  12. [12]
    United States Nuclear Tests: July 1945 through September 1992 (PDF) (DOE/NV-209 REV15), Las Vegas, NV: Department of Energy, Nevada Operations Office, December 1, 2000, archived from the original (PDF) on October 12, 2006, retrieved December 18, 2013
  13. [13]
    Yang, Xiaoping; North, Robert; Romney, Carl (August 2000), CMR Nuclear Explosion Database (Revision 3), SMDC Monitoring Research
  14. [14]
    Hansen, Chuck (1995). Swords of Armageddon. Vol. VII. Retrieved December 28, 2016.
  15. [15]
    Herken, Gregg (2003). Brotherhood of the Bomb.
  16. [16]
    Operation Upshot-Knothole Summary Report of the Technical Director. 1953. Retrieved February 17, 2019.
Bibliography
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